Death warmed over

Climate Variability, Climate Change and Fisheries Edited by Michael H Glantz Press Syndicate of the University of Cambridge

 
By Mitali Ghosh Ray
Published: Sunday 30 April 1995

SPECULATION is on about the effect of global warming on fish production. The world's marine population is, as it is, subjugate to various factors such as water temperature, salinity, ocean currents, predator-prey relationship, food and nutrient availability, rainfall and pollution due to human activity and new technologies.

This interesting and informative book aims to study the probable effect of global warming on fisheries, using the "forecasting by analogy approach". This, according to the editor, is an attempt to forecast society's ability to respond to the consequences of yet unknown environmental changes that might occur in future by looking at societal responses to recent environmental and legal changes. The book has 15 case studies of different fisheries around the world.

For instance, a combination of overfishing, management conflicts and climate changes contributed to the collapse of sardine fishing in California. An intense El Nino in the coastal and eastern equatorial Pacific Ocean in 1982-83 caused an upwelling in the higher latitudes of northeast Pacific. The production and collection of salmon along the US coast in 1983-84 dropped.

If the current rate of sea level rise continues, a study in the US gulf predicts, there will be a loss of production habitat for brown, white and pink shrimp. Global warming might also lead to the drying of Louisiana's estuaries due to drought in the Great Plain(plains?). Marsh loss and eventual decrease in prawn yield will be inevitable.

James R Macgoddwa looks at the human response to weather-induced catastrophes in fisheries in west Mexico. Sea lamprey invaded the Upper Great Lake(lakes?) (Huomx, Michigan and Superior). Their prey included trout, lake whili fish and salmon. Many discrete stocks of salmonoid are extinguished due to predation of sea lamprey(whoa! what means?).

It isn't true that the entire fallout of global warming will be harmful to the fisheries. It may have a favourable effect on Atlanto-Scandinavian herring, as is evident from the appearance of stronger classes during the warm epoch, compared to the cold period.

---Mitali Ghosh Ray is with the Indian Council of Agricultural Research.

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